Isometrus kovariki, Sulakhe & Dandekar & Mukherjee & Pandey & Ketkar & Padhye & Bastawade, 2020

Sulakhe, Shauri, Dandekar, Nikhil, Mukherjee, Shomen, Pandey, Malay, Ketkar, Makarand, Padhye, Anand & Bastawade, Deshabhushan, 2020, A new species of Isometrus (Scorpiones Buthidae) from southern India, Euscorpius 310, pp. 1-13 : 4-11

Isometrus kovariki sp. n.

( Figures 1–21 , 24, 28, 32 , Tables 1–4)

http: //zoobank. org/urn: lsid: zoobank. act: 225D3716-8AFB- 4A08-A01D-FFCEBEE276CF

TYPE LOCALITY AND TYPE REPOSITORY. India, Karnataka State, Bengaluru Urban District, Chikkadunnasandra , 12.85°N 77.76°E, 893 m a. s. l.; BNHS .

TYPE MATERIAL. India, Karnataka State, Bengaluru Urban District, Chikkadunnasandra , 12.85°N 77.76°E, 893 m a. s. l. , 1♂ (holotype, BNHS SC 161 ), 29 August 2019 , 6♂ (paratypes, INHER- 146, 149, 151, 152, BNHS SC 163 , 164 ) , 2♀ (paratypes, INHER-148, BNHS SC 162 ), 29 August 2019. All specimens collected by S. Mukherjee, S. Sulakhe, M. Ketkar, S. Deshpande & M. Kulkarni.

ETYMOLOGY. The species epithet is a patronym honoring František Kovařík for his remarkable contribution to the scorpion taxonomy of the world. Suggested common name: Kovařík’s Tree Scorpion.

DESCRIPTION (♂ holotype).

Coloration ( Figs. 2, 3 , 9, 10 ). Body and appendages light yellowish brown and variegated with blackish brown stripes and spots; light brownish to yellowish last metasomal segment, more darker on posterior portion; pedipalp fingers dark brownish at the base. Ventral portion uniformly yellow and sternite V with few dark spots. Basal segments of chelicera dorsally yellowish with blackish reticulation ending anteriorly into blackish transverse patch; ventral portion of chelicera yellowish; fingers of chelicera dark brown with tip of the fingers black. Telson uniformly brown in color.

Carapace ( Figs.18, 20 ). Surface granular throughout with mixed granules, more closely granular in inter-ocular area and median posterior ocular area. Carapace without carinae, median supra-ocular area, with mixed granulation. A pair of median eyes situated anteriorly in the ratio 1:2.2 (Ratio of median eyes to anterior margin and median eyes to posterior margin). Anteriolateral ocular tubercle granular, provided with 5 pairs of lateral ocelli. Three pairs of subcontiguous lateral ocelli and two micro-ocelli situated behind the lateral ocelli. Median longitudinal furrow visible only till the anterior portion of median eyes. Anterior margin smooth with deep emargination. Lateral margins finely crenulated below the lateral ocelli. Posterior margin almost entirely smooth.

Chelicerae ( Fig. 6 ). Characteristic of the family Buthidae . Basal segments and movable fingers with short and firm setae on the basal and ventral surfaces. Dorsal surface of basal segment with two prominent tubercles on anterior portion.

Pedipalp ( Figs. 12–17 , 24 ). Femur with 5 carinae (dorsal exterior, dorsal interior, exterior median, interior median and exterior ventral). Exterior median carina with few granules more prominent and subtriangularly tuberculate.All remaining carinae are evenly crenulated. Intercarinal space very weakly granular except ventral surface with few closely set granules on proximal portions. Patella with 7 distinct carinae (Dorsal median, dorsal interior, dorsal exterior, exterior median, ventral exterior, interior median and ventral interior). Dorsal exterior, dorsal interior and dorsal median carinae granular. Interior median carina strongly tuberculated with few subdenticulate granules. Exterior median carina weakly granular. Ventral interior carina evenly granular. Ventral exterior carina weakly granular on proximal portion and obsolete on distal portion. Intercarinal space almost entirely smooth. Manus almost smooth. Fixed fingers with 1 smooth and obsolete carina on dorsal exterior surface. Fixed and movable finger armed with 6 rows of linear denticles with one external denricle only on movable finger. Trichobothrial pattern typical for the genus.

Legs ( Figs. 2, 3 , 7, 8 ). Femur and patellae carinated. All carinae granular. Tibiae 3 and 4 without tibial spur. All legs with a pair of pedal spurs. Tarsomere covered with long delicate setae arranged in parallel rows on ventral side. Tarsomere I provided with tuft of short, stout blackish setae on ventral side. Tarsomere II compressed laterally and ventrally provided with paired row of short, pointed, anteriorly directed, closely placed setae.

Genital operculum ( Figs. 4 , 11 ). Wider than long, elliptical, separated with a pair of short male genital papillae.

Pectines ( Figs. 4 , 11 ). Basal piece rectangular, deeply notched on anterior median margin. Posterior margin of basal piece curved; smooth on surface with a parallel wide sub-basal piece along the posterior margin. Pectin 5 times longer than its width, marginal lamella of 3 digits and median lamella of 6 digits, outer margin armed with a row of stout short red setae and few setae on surface. Fulcra 15, roughly triangular each armed with few short red setae, placed in between adjacent pectinal teeth. Teeth 16, strong and stout.

Mesosoma ( Figs. 2, 3 , 7–10 ). Tergites I – V sparsely and finely granular and provided with a short median carina. Posterior and lateral margins granular. Tergite VI with continuous median carina. Tergite VII narrowed posteriorly, granular, provided with 2 pairs of lateral granular carinae, present only on 2/3 posterior portion and ends abruptly. A broad median carina limited to anterior 1/3 of median portion. Sternites III– VI almost entirely smooth with a pair of spiracles. Sternite V exceptionally smooth. Sternite VII smooth on posterior margin while finely crenulated to serrated on lateral margins; with 2 pairs of granular carinae; median carinae restricted to posterior 2/3 portion; lateral carinae present in the middle half region.

Metasoma ( Figs. 2, 3 , 7–10 ). All segments longer than wide; basal segment 1.8 times longer than wide. Segment I with 5 pairs of carinae (dorsal, dorso-lateral, lateral, ventrolateral and ventral) weakly granular. Intercarinal space weakly and finely granular, anterior margin smooth. Segments II and III provided with 4 pairs of carinae (dorsal, dorsolateral, ventrolateral and ventral). Intercarinal portion irregularly granular, dorso-lateral and dorsal carinae posteriorly ending into weak subtringular tubercles. Segment IV with 4 pairs of weakly granular carinae (dorsal, dorsolateral, ventrolateral and ventral). Dorsals ending into very weak subtringular tubercles. Intercarinal space weakly and irregularly granular. Segment V with 7 carinae (dorsal, dorsolateral and ventrolateral pairs and a single ventral); dorsal carinae weakly, sparsely granular. Dorsolateral carinae present throughout. Laterals totally absent. Ventrolateral carinae and single ventral median carina granular and ending posteriorly into a weakly granular anal rim. Intercarinal space irregularly and weakly granular than segments I–IV.

Telson ( Figs. 5 , 30 ). Telson with stout vesicle, bulbous on distal portion and smooth on dorsal surface. Lateral surface demarcated with weakly granular ridge. Ventral median carina very weakly granular ending into triangular, subacular, pointed nodule, armed with a pair of minute denticle on inner margin. Ventral portion with 2 pairs of sparsely and finely granular carinae. Intercarinal space weakly and finely granular. Aculeus elongated, sharp and moderately curved.

Measurements. See Table 1.

SEXUAL DIMORPHISM. Male genital operculum partially exposed on posterior portion, from which a pair of small genital papillae is seen. In females the genital operculum is separated with a median suture covering the female genital orifice ( Figs. 4 , 11 ).

AFFINITIES. Isometrus kovariki sp. n. differs from all other Indian species of Isometrus by a raw genetic distance of about 10 to 16 % ( Table 3 ) (see below). It is distinguished from its congeners based on the following set of morphological characters:

1. Average total length larger in Isometrus kovariki sp. n. as opposed to I. thurstoni . Males (51.3 ± 6.1mm vs 43.0 ± 7.0mm), females (42.3 ± 1.9mm vs 39.6 ± 3.0mm) ( Table 2 ).

2. Metasomal length to carapace length ratio in males 5.1– 5.8 as against 6.3–7.1 in I. thurstoni , 7.4–7.6 in I. tamhini , 6.0– 7.2 in I. amboli and 7.6 in I. maculatus ( Table 2 ).

3. Carapace granular throughout with mixed granules, more closely granular in inter-ocular area and median posterior ocular area as opposed to sparsely granular with some areas without granules in I. thurstoni ( Figs. 18–21 ).

4. Anterio-lateral margin of carapace curved near the lateral eyes as opposed to anterio-lateral margin of carapace sharply curved near the lateral eyes in I. thurstoni ( Figs. 18–21 ).

5. Telson length greater than or equal to 4 times the telson width in males as opposed to less than or equal to 4 times in I. thurstoni ( Table 2 , Figs. 28–31 ).

6. Anterior margin of carapace with deep emargination in Isometrus kovariki sp. n. and I. thurstoni as opposed to anterior margin of carapace with shallow emargination in I. tamhini and I. amboli ( Figs. 18–21 ).

7. Ventral median carina on vesicle weakly granular in Isometrus kovariki sp. n. and I. thurstoni as opposed to strongly granular in I. tamhini and I. amboli ( Figs. 28–31 ).

All the diagnostic characters mentioned above are based on all the specimens collected and studied (including holotype and all paratypes).

DISTRIBUTION, HABITAT AND ECOLOGY. The new species is currently known only from the type locality in southern peninsular India. It is an approximately 10–15 year old Acacia auriculiformis plantation, on the outskirts of the Bengaluru city. In this area they were found to be most active during summer and used both the bark of the trees and leaf litter (in equal numbers) for ambushing their prey such as field cockroaches ( Blatella sp.) and crickets. However during the rainy season they were largely found ambushing only on the trees. The scorpions are not active during winter (December, January); however, they start becoming active by the end of February. Live individuals brought and maintained in the lab of S.M. (at Azim Premji University) indicated that this species breeds in May (summer), and their clutch size ranges from 12–20 individuals (n=4). The juveniles dispersed after their first moult which occurred two days after birth. ( Figs. 22 , 23 ).

Figures

Figure 1. Isometrus kovariki sp. n., male holotype, in vivo habitus.

Figures 2–6. Isometrus kovariki sp. n., male holotype, dorsal (2) and ventral (3) views, sternopectinal area (4), telson in lateral view (5) and chelicera in dorsal view (6).

Figures 7–8. Isometrus kovariki sp. n., male holotype in dorsal (7) and ventral (8) views under UV fluorescence.

Figures 9–11. Isometrus kovariki sp. n., female, paratype, BNHS SC 162, in dorsal (9) and ventral (10) views, and sternopectinal area (11).

Figures 12–22: Isometrus kovariki sp. n. Figures 12–18, 20. Male, holotype, pedipalp chela dorsoexternal (12) and ventral (13), patella dorsal (14) and external (15), and femur dorsal (16) and internal (17) views. Trichobothrial pattern indicated by yellow circles. Carapace under white light (18) and UV fluorescence (20). Figures 19, 21. Female, paratype, BNHS SC 162, carapace under white light (19) and UV fluorescence (21). Figure 22. Type locality, a view of dense plantation with tall trees.

Figures 23–35: Figure 23. Distribution of Isometrus kovariki sp. n. Figures 24–27: Comparison of pedipalp movable finger dentition. Figures 28–31: Comparison of telson in ventral view. Figures 32–35: Comparison of metasoma II–III in lateral view. Figures 24, 28, 32. I. kovariki sp. n., male, holotype. Figures 25, 29, 33. I. thurstoni, male, INHER-SC-139. Figures 26, 30, 34. I. tamhini, male, holotype. Figures 27, 31, 35. I. amboli, male, holotype.